Subtractive color film



Patented Jan. 9, 1940 UNITED ,STATES PATENT OFFICE assignor, by mesne assignments, to Agia Ansco Corporation, Binghamton, N. Y., a corporationv oi Delaware No Drawing. Application November 3. 1937,

Serial No. 172,652. In Germany November 8,

Claims.

The present invention relates to subtractive color films.

One of its objects is to provide an improvement in a process of producing subtractive color films. 5 vFurther objects will be seen from the following detailed description.

A known device in cinematography consists in r causing a scene to become increasingly darker and finally to end in complete darkness. 'Zihis l0 fading-out" is arranged already during the taking of the film either by gradually making the whole field of vision uniformly darker or by alteration oi diaphragms having circular or straight or otherwise shaped boundaries which move unii'ormly from the edges of the picture towards the centre or in the reverse direction. In the case of black-and-white films this can be done without any undesired secondary efiect on the positive film which is later prepared for projection. This is not the case, however, when the picture is taken on a subtractive multi-color film, particularly when the picture is to consist of puredvestuii. images without any embedded silver image. Since the gradation curves of the individual emulsion layers contributing to the synthesis of the picture do not coincide or 'at least do not run parallel in all zones of exposure, it generally happens that a correct adjustment oi the colors in the several layers yielding in conjunction a grey is only round over a relatively small range or ex-' posures. A variation in the exposure in either direction from this range then results in a predominance 01 one 01' the colors. Thus, if a scene ,on a multi-color material of this kind is faded out it becomes ior example greener as it darkens.

4; colored. As the scene iades out. however. the.

whole picture passes gradually into the dark color which is now perceptible to the eye since the contrast is now lacking.

By this invention this fault in the fading-out so canbecorrectedbygivlngthefilmintheregions o! the desired fading-out an additional coloring with a pure black or grey dyestuii or with a dyestufi whose color is complementary to the incorrectly predominating color. In the type of fading-out consisting in a uniform darkening of the whole field of vision the desired result can be 5 obtained by progressively increasing the duration of immersion of the film in the dyestufl solutioh or by applying by means of a roller a solution of increasing concentration (or vice versa) In the case oi fading-out produced by movement 01' 1o the boundary of the picture, that is to say for in-' stance by means of a concentric darkening proceeding from the edges of the picture towards the ture maintains its normal density and only the 25 additional coloring is increased in density until it is finally black.

What I claim is:

1. In a process oi producing iade-outs in a subtractive 3-color motion picture film containing 0 three diiierently colored dye images, in'which the fade-outs are produced by decreasing the expo'sure oi successive frames of the color image record, the improvement which consists in uniior'mly applying to each of said frames an addi- 5 tional dye complementary in light-absorptionto the color tending to predominate and in such quantity as to give a neutral black with said color.

2. The process as defined in claim 1, wherein said additional dye is applied with the aid oi an imbibition method. 4 3. The process as defined in claim 1. wherein said additional dye is applied by hand with a stencil.

4. The process as defined in claim 1. wherein said additional dye is applied by dyeing with a variation in the period 0! dyeing.

5. The process as defined in claim 1. wherein said additional dye is applied by dyeing with a variation of the concentration oi the dye.

GERD. 

